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Trilobites are not isopods

And the lies were just so painfully blatant: as an example, he claimed that trilobites weren’t old and they weren’t extinct, and to ‘prove’ his claim, he showed a picture of an arctic isopod and announced that there it was, alive and crawling, proof that the biology professors have all been lying to you.

My comments:
Young-earth creationist Kent Hovind includes in his talks an assertion that trilobites are still around because he has—ta-da!—a picture of an isopod. That’s like saying that horseshoe crabs live in the Prairies because you found a grasshopper. But “Dr.” Hovind seems unaware of his mistake. It’s almost as if Hovind’s attitude towards God’s creations is, “If you’ve seen one bug, you’ve seen them all.” Is it a lie if you don’t care?Isopods are only distantly related to trilobites. Allow me to introduce Hovind to the Tree of life page for arthropods.
The further apart the names are in the list, the more distantly related they are. Trilobites are distinguished by the three lengthwise sections of the body. (Harvard University shows a nice selection of trilobite species.) They are also extinct, as shown by the little dagger beside their name. I know of no living crustaceans with bodies divided into three lengthwise lobes. Here is a fossil of a trilobite:
Here is an isopod:

You’ve seen them, because sowbugs and pillbugs are isopods. Sowbugs and pillbugs are those little, segmented grey bugs that hide in damp places. Pillbugs curl into a ball when you pick them up; sowbugs just run away. I remember learning in school that they are crustaceans and breathe with gills, so they must live around moisture.

Both trilobites and isopods are in class Arthropoda (“jointed legs”). To call them the same is like saying or that a clam is the same as an octopus. (Both are in class Mollusca.) To find the isopod branch of the arthropod tree, click on Crustacea, then Malacostraca, then Peracarida, then Isopoda. (The middle picture on the Isopod page shows a parasite that enters the mouth of a fish, then eats the tongue and lives in its place.)

But what is Hovind’s point? Even if an old form persists, “cousin” groups could still have evolved from their common ancestors, and evolutionary pressures continue to operate today. Is it simply a chance for him to laugh at the foolish scientists who can tell the difference between a crustacean or a trilobite? Besides being a cheap shot, it’s a remarkably useless one.

16 Responses to “Trilobites are not isopods”

“The further apart the names are in the list, the more distantly related they are.”

I probably don’t know how to read the taxonomy chart so please correct me if I’m wrong, but it seems to me that the four main branches in that tree are sibling branches. If that is the case, then couldn’t they be reordered so that the branch leading to trilobites comes immediately after the branch leading to hexapoda and crustacea, without changing the meaning?

uh. a pillbug and many similar living species are the closest things to trilobites alive from a morphological point of view. they represent a very basal bug form regardless if there are other closer relatives to the trilobite that have derived significantly.

They are sister groups in the arthropod clade–organisms with jointed legs, as their name states, because they have external skeletons. But to say that trilobites are the same as isopods is the same as saying that spiders are millipedes, scorpions are water fleas, or barnacles are butterflies. The trilobites are extinct. Hovind’s point was that trilobites are not extinct. He is wrong.

Trilobites are distinguished by the three lengthwise sections of the body

hahahaha
I looked up these three sections of the trilobite:
Head Body/Thorax Tail/Abdomen

The SAME 3 lengthwise segments of the isopod.

Other than that one point, he does not distinguish the isopod or the trilobite in any biological manner. This makes me think the isopod is a modern trilobite if there is nothing biological to distinguish the 2.

I’m impressed that not only did you fail to read the chart, which clearly shows that isopods, spiders, and butterflies are equally distant from trilobites; you also don’t understand what “lengthwise” means. The three lengthwise lobes of a trilobite are left, centre, right. Meanwhile, an isopod has a cephalothorax, which is a head fused with the first thoracic segment; then two to nine thoracic segments; then about six abdomen segments; and finally tail segments. It’s not exactly the classic crosswise division into head, thorax, and abdomen, although you can find it over-simplified to such in lessons for fourth-graders

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